• Communications for Statistical Applications and Methods
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• 제4권1호
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• pp.207-218
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• 1997

We consider two models for the growth of population with overlaping generations. First, the model we will describe is basically the model given by Leslie(1945). This is only a one-sex model of population age structure and growth. Next, we introduce a model in which couples must be formed before reproduction occurs. If the maximum number of couples is formed, and if the couples are only formed from fermales of age x-a and males of age x at time t, $\alpha$ > 0. Then, we will solve the renewal equations for the reproductive value.

• The Korean Journal of Ecology
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• 제17권3호
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• pp.415-424
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• 1994

Community structure, size and age distribution of tree species of the subalpine Korean fir (Abies koreana) forest at the elevation of 1, 400~1, 700m were strudied in the north-west side of Chonwangbong Peak (1915m) in Mt. Chiri for the purpose of better understanding of the population dynamics of Abies koreana. Eight 20m X 20m permanent quadrats were established in 1991, and trees $\geq$ 2.5cm DBH for all species were marked with numbered aluminum tag, and saplings of Korean fir and Korean pine (Pinus koraiensis) were also tagged with aluminum sheet. These two conifer species comprised more than 60% of the total density and total basal area of the community. Quercus mongolica and Acer pseudo-sieboldianum were subdominats. Oridination study showed that cool temperate species such as Sorbus commixta, Betula costata, Acer tschonoskii and Acer ukurunduense occurred in close association with Abies koreana and Pinus koraiensis. Major tree species, especially Abies koreana and Pinus koraiensis, were well represented in samller size classes, indicating that they were regenerating well. Age distributuion of the Abies koreana and Pinus koraiensis showed that the former has longer physiological longevity than the latter, and that establishment were episodic and varied with sites, which implies the importance of the role of natural and artificial disturbances in this Abies kireana forest.

• 한국콘텐츠학회논문지
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• 제7권8호
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• pp.163-173
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• 2007

Need 나 want 시대를 지난 지금의 시대적 상황을 Feeling 시대라고 용어를 정리 하면서, 소비자 심리와 행동, 사회 문화적 변용을 근거로 한 의미 작용을 분석하였다. 이를 근거로 하여 $\sqrt{3}$비례를 기준으로 한 정삼각형의 기본조형을 얻어 유통, 판매, 할 수 있는 상품의 실질적 조형에 접근하였고, 상품 사용 후 여러 가지 형태로 다변화 할 수 있는 유희성과 재활용적 조형을 구축하였다. 이는 탈 코드화된 패키지조형의 창조라는 점에 큰 의미를 갖는다. 또 패키지 조형의 물리적, 기능적 가치뿐만 아니라 심리적 사회문화적 해석의 기능과 소비자의 정체성이 교감될 수 있도록 적절한 조형적 기호(semiotics)가 연구되어졌다.

• 한국농촌생활과학회지
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• 제7권1호
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• pp.69-80
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• 1996

The purpose of this study is to offer basic data of education to improve farm lives though investigating rural homemakers' life style. The results of this study are as follows : 1. The life structure of rural homemakers was classified into two structures as a material resources and human resources. The life style of rural homemakers was classified into systematical life style, traditional value style, social active style, and progressive active style. 2. The life styles of rural homemakers according to social population variance were as follows. The lower of age, homemakers whose family incomes more 30 million won or below 10 million won, who has religions, who employed in livestock were showed at very systematical life style. The homemakers who live in mountain village, higher the much age becomes, and the education level become lower, have showed traditional value style. Rural homemakers the lower of age, the higher incomes, composed of single parent ＋ children who remain single were appeared social active style. Rural homemakers the lower of age, the more shortened farm life periods, who employed in livestock were appeared progressive active style. 3. Systematical life style was more affected by material resources structure, traditional value style was affected by material resources. And social active style was more affected by human resources, progressive active style was affected by human resources.

• Asian-Australasian Journal of Animal Sciences
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• 제5권1호
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• pp.165-171
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• 1992

The developmental process of the epididymis was investigated in Meishan boars from 1 to 364 days of age. Epididymal weight increased rapidly between 45 and 150-180 days of age. The diameter and epithelial area of the epididymal ducts greatly increased up to 105-120 days of age. At 1 day of age, the central and distal cauda already had a pseudostratified epithelium surrounded by smooth muscle. At 60-75 days of age, the central and distal caput, corpus, and proximal cauda revealed a well-developed structure of the epithelium. The proximal caput showed a tall, irregular and vacuolar epithelium at 105-120 days of age. PAS-positive contents in the lumen of the caput, corpus and cauda epididymides were first detected at 60-75, 45-60 and 1-30 days of age, respectively. Moreover, in the central and distal caput, PAS-positive granules appeared at 60-75 days of age, and increased until 105-120 days. These results suggest that the epididymis develops completely by approximately 120 days of age, though its weight increases rapidly up to 150-180 days. Thus, it appears that development of the epididymis occurs at an earlier age in Meishan boars than in European and American breeds.

• 수산해양기술연구
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• 제36권3호
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• pp.222-233
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• 2000

지금까지의 한국 연근해산 참조기의 연령사정은 전부가 비늘에 의한 것이었다. 본 연구에서는 최초로 참조기의 이석을 연령형질로 사용하여 가장 적절한 연령사정 방법을 모색해 보았다. 참조기의 이석은 외관상으로는 윤문이 보이지 않으므로 얇게 절단하여 판독하는 방법(thin section method)이 적절하며, 성장 초점을 기준으로 가로, 세로, 대각선 세 방향으로 얇게 절단하여 윤문이 가장 선명하게 나타나는 방향을 알아본 결과 세로 방향으로 절단했을 경우가 윤문의 판독이 가장 용이하였다. 체장-체중 관계식과 성장식의 추정에서는 지금까지의 성장에 관한 연구에서는 고려되지 않았던 오차구조를 밝혀 매개변수의 추정에 정확성을 기하였다. 체장-체중 관계에서는 체장이 증가함에 따라 오차도 증가하는 곱의 오차구조를 가지며 관계식은 W=$0.0049L^{3.2153}$으로 나타났다. 성장식에서는 오차가 연령이 증가함에 따라 일정한 합의 오차구조를 가지며 비선형 회귀분석에 의한 von Bertalanffy 성장식은 $L_{t}$=37.11(1-e$\^$-0.20+1.88/)로 나타났다.

• The Korean Journal of Ecology
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• 제16권3호
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• pp.317-327
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• 1993

Stands profiles, yearly changes in growth of annual rings, age and diameter structure, and spatial distribution pattern of individuals in the Pinus densiflora stands around the Yeocheon industrial complex were investigated. Growth of annual ring in Pinus densiflora, which survived when vegetation of this area was damaged by air pollutants, was suppressed for about 10 years since 1974 when factories in this area began to operate, but since then such suppressed growth tended to be recovered. It was supposed that the suppresed growth was originated from air pollution and that improvement of growth since the suppressed period was due to the release from competition with them by death of neighbouring trees and the resuction of the amount of air pollutants. Physiognomy of Pinus densiflora stands showed mosaic pattern composed of different patches. Spatial distribution pattern of individuals an stand profiles were similar to those of Pinus densiflora stands regenerated after natural and artificial disturbances. In an age distribution diagram, age of Pinus densiflora population ranged from 1 to 33 years, Among these individuals were recrited corresponded to the suppresed period of growth of annual ring in Pinus densiflora survived when the vegetation was damaged by air pollution. On the other hand, from the result of analysis of frequency distribution diagram of diameter, it was postulated that even if whis Pinus densiflora community can be maintained as it is for the time being, it might be changed to Quercus community with the lapse of time. Regeneration; Pinus densiflora; Air pollution; Annual ring; Age structure; Diameter structure; Quercus spp. In these analyses, factors for individual recognition and species recognition were suggested.

• Journal of Ecology and Environment
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• 제44권3호
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• pp.178-184
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• 2020

Background: Geladas (Theropithecus gelada), endemic to Ethiopia, are distributed closely related to the escarpments and gorge systems of the country, and large populations are found in the Simien Mountain National Park. This study was conducted in Eastern Tigray, Northern Ethiopia, from February 2018 to August 2019 in order to determine population size and composition of geladas. Total count method was used to estimate the population structure of geladas. Observations of the group of geladas based on body size and morphological characteristics were used to classify age and sex categories of the population. SPSS Version 20 was used to analyze the data. Chi-square test was used to compare sex ratio of geladas and population size among the counting sites between wet and dry seasons. Results: A total of 112 and 99 individual of geladas were counted during wet and dry seasons, respectively. Of the average gelada population recorded in this study, 11.4% were adult males, 30.3% were adult females, 12.8% were sub-adult males, 25.6% were sub-adult females, and 19.9% were unidentified juveniles. However, there was no statistically significant difference among the various age and sex groups of geladas counted during wet and dry season (χ² = 2.6, DF = 4, P > 0.05). Variations of group size along seasons were observed in this study. Sex ratio of adult male to adult female was 1:2.6 and 1:2.7 during the dry and wet seasons, respectively. Conclusion: Very small gelada population size was recorded in the current study. An average of 105.5 geladas was recorded during the study period. As this is the first report of gelada population in escarpments of Eastern Tigray, population trend of the geladas cannot decide based on the current study.

• 환경생물
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• 제37권3호
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• pp.335-342
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• 2019

The purpose of this study was to investigate the toxic effects of zinc in collembolan Paronychiurus kimi at the individual (survival and juvenile production) and population (population growth and age structure) levels after 28 days of exposure in artificially spiked soil. These toxic effects were interpreted in conjunction with the internal zinc concentrations in P. kimi. The EC₅₀ value for juvenile production based on the total zinc concentration was 457 mg Zn kg^-1 dry soil, while the LC₅₀ value for adult survival and r_i=0 value for population growth were within the same order of magnitude (2,623 and 1,637 mg Zn kg^-1 dry soil, respectively). Significant differences in adult survival, juvenile production, and population growth compared with the control group were found at concentrations of 1,500, 375, and 375 mg Zn kg^-1 dry or higher, respectively, whereas significant differences in the age structure, determined by the proportion of each age group in the population, were observed in all treatment groups. It appeared that the internal zinc level in P. kimi was regulated to some extent at soil zinc concentrations of ≤375 mg Zn kg^-1 dry soil, but not at high soil zinc concentrations. These results indicate that, despite zinc being regulated by P. kimi, excess zinc exceeding the regulatory capacity of P. kimi can trigger changes in the responses at the individual and population levels. Given that population dynamics are affected not only by individual level but also by population level endpoints, it is concluded that the toxic effects of pollutants should be assessed at various levels.

• Journal of Ecology and Environment
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• 제42권4호
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• pp.292-297
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• 2018

Background: Gelada baboon is one of the endemic mammals of Ethiopia residing in different highlands. The population structure and habitat use of gelada baboon in Wof-Washa particularly Gosh Meda area was investigated from September 2016 to August 2017. Total counting method was used to collect data on the population status by dividing the study area in to four blocks, namely, Kundi, Arbgebeya, Goshber, and Goshmeda. Data were analyzed using SPSS software. The age-sex category and the numbers of geladas found within the different blocks were analyzed using one-way ANOVA, and paired t test was also used to analyze the pair wise comparison of the different age and sex categories during both dry and wet seasons. Results: A total of 435 and 471 gelada baboons were counted during the wet and dry seasons, respectively. The maximum group size consisted of 178 individuals whereas the minimum group size contained 53 individuals. Out of the total population adult females accounted for 54.7% in the wet and 54.56% in the dry seasons. There was a significant difference among the age-sex categories in both the wet ($F_{2432}=630$, P < 0.05) and dry ($F_{2468}=696.6$, P < 0.05) seasons. The male to female ratio was 1:5.7 during wet season and 1:5.8 during dry season. So that the population will have a better chance to increase in the study area. Conclusion: Wof-Washa Forest could be a good site for eco-tourism activities due to the presence of endemic animals and its scenic beauty. However, the quality of the habitat is decreasing due to livestock grazing, agricultural expansion, and invasion of exotic plants species. Therefore, appropriate conservation measures should be implemented to conserve gelada baboon in particular and other wildlife resources in general.